/*
 * Copyright 2016 The Netty Project
 *
 * The Netty Project licenses this file to you under the Apache License,
 * version 2.0 (the "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at:
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 */
package io.netty.util.internal;

import java.io.IOException;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.NetworkInterface;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.SocketAddress;
import java.net.SocketException;
import java.net.SocketPermission;
import java.net.UnknownHostException;
import java.nio.channels.DatagramChannel;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.security.PrivilegedActionException;
import java.security.PrivilegedExceptionAction;
import java.util.Enumeration;

/**
 * Provides socket operations with privileges enabled. This is necessary for applications that use
 * the {@link SecurityManager} to restrict {@link SocketPermission} to their application. By
 * asserting that these operations are privileged, the operations can proceed even if some code in
 * the calling chain lacks the appropriate {@link SocketPermission}.
 */
public final class SocketUtils {

  private SocketUtils() {
  }

  public static void connect(final Socket socket, final SocketAddress remoteAddress,
      final int timeout)
      throws IOException {
    try {
      AccessController.doPrivileged(new PrivilegedExceptionAction<Void>() {
        @Override
        public Void run() throws IOException {
          socket.connect(remoteAddress, timeout);
          return null;
        }
      });
    } catch (PrivilegedActionException e) {
      throw (IOException) e.getCause();
    }
  }

  public static void bind(final Socket socket, final SocketAddress bindpoint) throws IOException {
    try {
      AccessController.doPrivileged(new PrivilegedExceptionAction<Void>() {
        @Override
        public Void run() throws IOException {
          socket.bind(bindpoint);
          return null;
        }
      });
    } catch (PrivilegedActionException e) {
      throw (IOException) e.getCause();
    }
  }

  public static boolean connect(final SocketChannel socketChannel,
      final SocketAddress remoteAddress)
      throws IOException {
    try {
      return AccessController.doPrivileged(new PrivilegedExceptionAction<Boolean>() {
        @Override
        public Boolean run() throws IOException {
          return socketChannel.connect(remoteAddress);
        }
      });
    } catch (PrivilegedActionException e) {
      throw (IOException) e.getCause();
    }
  }

  public static void bind(final SocketChannel socketChannel, final SocketAddress address)
      throws IOException {
    try {
      AccessController.doPrivileged(new PrivilegedExceptionAction<Void>() {
        @Override
        public Void run() throws IOException {
          socketChannel.bind(address);
          return null;
        }
      });
    } catch (PrivilegedActionException e) {
      throw (IOException) e.getCause();
    }
  }

  public static SocketChannel accept(final ServerSocketChannel serverSocketChannel)
      throws IOException {
    try {
      return AccessController.doPrivileged(new PrivilegedExceptionAction<SocketChannel>() {
        @Override
        public SocketChannel run() throws IOException {
          return serverSocketChannel.accept();
        }
      });
    } catch (PrivilegedActionException e) {
      throw (IOException) e.getCause();
    }
  }

  public static void bind(final DatagramChannel networkChannel, final SocketAddress address)
      throws IOException {
    try {
      AccessController.doPrivileged(new PrivilegedExceptionAction<Void>() {
        @Override
        public Void run() throws IOException {
          networkChannel.bind(address);
          return null;
        }
      });
    } catch (PrivilegedActionException e) {
      throw (IOException) e.getCause();
    }
  }

  public static SocketAddress localSocketAddress(final ServerSocket socket) {
    return AccessController.doPrivileged(new PrivilegedAction<SocketAddress>() {
      @Override
      public SocketAddress run() {
        return socket.getLocalSocketAddress();
      }
    });
  }

  public static InetAddress addressByName(final String hostname) throws UnknownHostException {
    try {
      return AccessController.doPrivileged(new PrivilegedExceptionAction<InetAddress>() {
        @Override
        public InetAddress run() throws UnknownHostException {
          return InetAddress.getByName(hostname);
        }
      });
    } catch (PrivilegedActionException e) {
      throw (UnknownHostException) e.getCause();
    }
  }

  public static InetAddress[] allAddressesByName(final String hostname)
      throws UnknownHostException {
    try {
      return AccessController.doPrivileged(new PrivilegedExceptionAction<InetAddress[]>() {
        @Override
        public InetAddress[] run() throws UnknownHostException {
          return InetAddress.getAllByName(hostname);
        }
      });
    } catch (PrivilegedActionException e) {
      throw (UnknownHostException) e.getCause();
    }
  }

  public static InetSocketAddress socketAddress(final String hostname, final int port) {
    return AccessController.doPrivileged(new PrivilegedAction<InetSocketAddress>() {
      @Override
      public InetSocketAddress run() {
        return new InetSocketAddress(hostname, port);
      }
    });
  }

  public static Enumeration<InetAddress> addressesFromNetworkInterface(
      final NetworkInterface intf) {
    return AccessController.doPrivileged(new PrivilegedAction<Enumeration<InetAddress>>() {
      @Override
      public Enumeration<InetAddress> run() {
        return intf.getInetAddresses();
      }
    });
  }

  public static InetAddress loopbackAddress() {
    return AccessController.doPrivileged(new PrivilegedAction<InetAddress>() {
      @Override
      public InetAddress run() {
        if (PlatformDependent.javaVersion() >= 7) {
          return InetAddress.getLoopbackAddress();
        }
        try {
          return InetAddress.getByName(null);
        } catch (UnknownHostException e) {
          throw new IllegalStateException(e);
        }
      }
    });
  }

  public static byte[] hardwareAddressFromNetworkInterface(final NetworkInterface intf)
      throws SocketException {
    try {
      return AccessController.doPrivileged(new PrivilegedExceptionAction<byte[]>() {
        @Override
        public byte[] run() throws SocketException {
          return intf.getHardwareAddress();
        }
      });
    } catch (PrivilegedActionException e) {
      throw (SocketException) e.getCause();
    }
  }
}
